Represents the maximum payout of shares granted upon the actual performance against the Performance Measures.

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Represents the minimum payout of shares granted upon the actual performance against the Performance Measures.

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Represents information pertaining to period over which the relative total shareholder return is to be calculated to enable vesting of share-based payment awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount of expense for employee benefit and equity-based compensation.

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The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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Number of non-option equity instruments exercised by participants.

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Percentage of vesting of award under share-based payment arrangement.

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Value, after forfeiture, of shares granted under share-based payment arrangement. Excludes employee stock ownership plan (ESOP).

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Value, before forfeiture, of shares granted under share-based payment arrangement. Excludes employee stock ownership plan (ESOP).

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STOCK-BASED COMPENSATION - RSAs and RSUs (Details) - Senior Management - USD ($) $ in Millions				1 Months Ended		2 Months Ended	12 Months Ended
	Mar. 02, 2018	Jan. 17, 2017	Jan. 14, 2016	Feb. 28, 2018	Nov. 30, 2017	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2011
Performance-Contingent RSAs and RSUs
Stock-based compensation
Granted (in shares)								63,000
Vested (in shares)					63,000
Market-Based RSAs and RSUs \| 2016 Market-Based RSAs and RSUs
Stock-based compensation
Timeframe for calculation of TSR			2 years
Minimum payout of shares (in shares)			0
Maximum payout of shares (in shares)			328,688
Aggregate value to be recognized as compensation expense			$ 2.0
Reversal of previously recognized compensation expense						$ 0.2
Market-Based RSAs and RSUs \| 2016 Market-Based RSAs and RSUs \| Vested on February 20, 2018
Stock-based compensation
Vesting percentage			66.67%	66.67%
Market-Based RSAs and RSUs \| 2017 Market-Based RSAs and RSUs
Stock-based compensation
Timeframe for calculation of TSR		2 years
Minimum payout of shares (in shares)		0
Maximum payout of shares (in shares)		406,868
Aggregate value to be recognized as compensation expense		$ 3.2
Reversal of previously recognized compensation expense							$ 1.3
Market-Based RSAs and RSUs \| 2017 Market-Based RSAs and RSUs \| Vested on February 20, 2019
Stock-based compensation
Vesting percentage		66.67%
Market-Based RSAs and RSUs \| 2018 Market-Based RSAs and RSUs
Stock-based compensation
Timeframe for calculation of TSR	3 years
Aggregate value to be recognized as compensation expense	$ 1.7
Market-Based RSAs \| 2016 Market-Based RSAs and RSUs
Stock-based compensation
Granted (in shares)			282,394
Vested (in shares)				118,821
Forfeited (in shares)				59,411		34,721
Stock-based compensation, net							$ 0.7
Market-Based RSAs \| 2016 Market-Based RSAs and RSUs \| Vested on February 20, 2018
Stock-based compensation
Exercised (in shares)				69,440
Market-Based RSAs \| 2016 Market-Based RSAs and RSUs \| Vested on February 20, 2019
Stock-based compensation
Vesting percentage			33.33%
Market-Based RSAs \| 2017 Market-Based RSAs and RSUs
Stock-based compensation
Granted (in shares)		353,508
Market-Based RSAs \| 2017 Market-Based RSAs and RSUs \| Vesting on February 20, 2020
Stock-based compensation
Vesting percentage		33.33%
Market-Based RSAs \| 2018 Market-Based RSAs and RSUs
Stock-based compensation
Granted (in shares)	111,668
Market-Based RSUs \| 2016 Market-Based RSAs and RSUs
Stock-based compensation
Granted (in shares)			46,294
Forfeited (in shares)						15,432
Market-Based RSUs \| 2016 Market-Based RSAs and RSUs \| Vested on February 20, 2018
Stock-based compensation
Exercised (in shares)				30,862
Market-Based RSUs \| 2016 Market-Based RSAs and RSUs \| Vested on November 20, 2018
Stock-based compensation
Vesting percentage			33.33%
Market-Based RSUs \| 2017 Market-Based RSAs and RSUs
Stock-based compensation
Granted (in shares)		53,360
Market-Based RSUs \| 2017 Market-Based RSAs and RSUs \| Vested on November 20, 2019
Stock-based compensation
Vesting percentage		33.33%
Market-Based RSUs \| 2018 Market-Based RSAs and RSUs
Stock-based compensation
Granted (in shares)	49,630